Washing machine and method of increasing balance of the drum of the washing machine

ABSTRACT

A washing machine having a cabinet, a drum for receiving laundry from its open end where the drum is rotatable around its longitudinal axis within the cabinet, a balancer having a mass channel, and a balancing weight where the mass channel extends in a direction from the lateral surface of the drum to the inside of the drum and receives the balancing weight and the balancing weight is movable within the mass channel along the direction of the extension of the mass channel is disclosed. The invention also relates to a method of increasing the balance of a drum rotating along its longitudinal axis within a washing machine, the method determining the unbalanced load of the laundry received by the drum, and moving a balancing weight in a direction between the lateral surface and the longitudinal axis of the drum.

TECHNICAL FIELD

The invention relates to a washing machine having a drum for receiving laundry and to a method of increasing balance of the drum of the washing machine.

TECHNOLOGICAL BACKGROUND

Conventional washing machines typically include a cabinet, which receives a stationary tub for containing wash and rinse water. A wash basket, which is also referred to as drum, may be rotatably mounted within the cabinet and in particular within washtub. A drive assembly and a brake assembly can be positioned relative to the washtub to cleanse the laundry placed into the drum. During, for example, a wash or spin cycle water is typically extracted from the laundry by rotating the drum containing the laundry at high rotational speeds. Centrifugal forces pull the majority of the water out of the laundry and through perforations in the rotating drum. A pump assembly can be used to rinse and drain the extracted water to a draining system.

The rotating drum is typically supported by a suspension system designed to dampen translational motion induced by an imbalance within the rotating drum. High stresses sometimes occur within the drum, drive system and suspension system during the high-speed spin action used for water extraction during normal wash cycles and may create imbalance within the washing machine. With an unbalanced distribution of the laundry, a force is generated which is proportional to the product of the mass of the laundry, the distance to the center of rotation of the drum and the square of the velocity of the drum. Small differences of the mass of the laundry at different locations can very easily generate large forces as a result of the high rotational velocities that may cause imbalance. When the laundry is out of balance, excess vibration and noise may be caused. Also, when a laundry is out of balance damage to the washing machine may be caused.

Known washing machines may employ various sensing techniques to determine, if the machine is operating with unbalanced laundry, which means that the laundry is not distributed in a balanced manner. One technique may include current or load sensing, imbalance sensing in the motor control, differences between target speed and current speed as well as 2D and 3D motion sensors. When an unbalanced load is detected during an extraction spin cycle, the machine is stopped and a signal is generated to alert the user to the unbalanced load. Sensing techniques involving current or load sensing in the motor control can be inaccurate due to additional loads on the motor other than the load provided by an imbalance due to laundry distribution.

The reason for vibration is the unbalanced weight of laundry inside the drum. Therefore, in order to reduce or cancel vibration, the unbalanced weight inside the drum has to be removed.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a washing machine, wherein an unbalanced load caused by an unbalanced distribution of laundry within the drum of the washing machine can be compensated.

According to the present invention, a new method is used to reduce or cancel vibration during spinning process of a washing machine. The invention is based on the finding, that a balanced opposite side of an unbalanced load is created to reduce centrifugal force of the unbalanced load.

In a first aspect, the present invention suggests a washing machine comprising:

-   -   a cabinet;     -   a drum for receiving laundry from its open end, wherein the drum         is rotatable around its longitudinal axis within the cabinet,     -   a balancer comprising a mass channel and a balancing weight,         wherein the mass channel extends at least in a direction from         the lateral surface of the drum to the inside of the drum and         receives a balancing weight, and the balancing weight is movable         within the mass channel along the direction of the extension of         the mass channel; and

The cabinet denotes a casing, wherein the drum of the washing machine is rotatably mounted. The cabinet has an opening at the front for loading laundry into the drum. At the opening of the cabinet, a door is provided for closing the cabinet during washing. The laundry will also be referred to as clothes. The washing machine further comprises a drum. The drum has an open end for receiving laundry. The open end is aligned with the opening in the cabinet. The drum is rotatable around its longitudinal axis. The longitudinal axis of the drum is thus the rotary axis of the drum. The drum is rotatably mounted in the cabinet and the drum can be driven by a motor in the washing machine.

According to the invention, the washing machine further comprises a balancer. Preferably, several balancers are provided. The balancer comprises a mass channel and a balancing weight.

The mass channel is provided at the lateral surface of the drum. The lateral surface denotes the wall of the drum that extends over the circumference of the drum and along the length of the drum. The lateral surface thus encloses the inside of the drum. According to the invention, the mass channel extends at least in a direction from the lateral surface of the drum to the inside of the drum. In particular, the mass channel can extend into the inside of the drum in the direction of a secant line of the circular cross section of the lateral surface. In a preferred embodiment, the mass channel therefore extends in a radial direction, that means extends in a direction between the lateral surface and the longitudinal axis of the drum. In a different embodiment, the mass channel extends into the inside of the drum in a direction of a secant line which is offset to the longitudinal axis of the drum. The mass channel can, for example, extend into the inside of the drum in a direction which is parallel offset to the radial direction. In a preferred embodiment, the mass channel extends in a direction between the lateral surface and the longitudinal axis of the drum.

The mass channel can also extend in the direction opposite to the direction from the lateral surface to the inside of the drum. In this case, the mass channel can extend both inwardly from the lateral surface as well as outwardly from the lateral surface.

The balancing weight is movable within the mass channel in the direction of the extension of the mass channel. The balancing weight is preferably oblong. In that case, the balancing weight can be moved in the longitudinal direction of the mass channel. If the mass channel extends in a radial direction, the balancing weight can move in a radial direction of the drum. The mass channel is a guide for the balancing weight. The balancing weight is movably held in the mass channel. Preferably, the balancing weight is held in the mass channel such that the balancing weight cannot be released from the mass channel. The mass channel may have at least one open end. Alternatively, the mass channel can be closed at both ends. The balancing weight is an element, which is apt for moving within the mass channel. The balancing weight may be an oblong element. In this case, the balancing weight can also be referred to as a pin or a rod. It is, however, also possible according to the invention, that the balancing weight is ball or a disc. In the mass channel, at least one balancing weight is provided. If more than one balancing weight is provided, the several balancing weights are preferably arranged adjacent to each other along the longitudinal direction of the mass channel. The outer dimension of the balancing weight(s), for example its outer diameter, is preferably selected to correspond to the inner dimensions of the mass channel, in particular its inner diameter.

The washing machine may further comprise a sensory circuit for determining the unbalanced load of the laundry received within the drum. The sensory circuit may be comprised in the control unit of the washing machine, which includes the control for the motor for rotating the drum. The sensory circuit may, however, also be a separate processing unit. The sensory circuit preferably serves for determining the position of the unbalanced load of laundry within the drum. In particular, the position of unbalanced load can be a first section along the lateral surface of the drum, where the weight of laundry present at that section is higher or lower than the weight of laundry at a second section of the lateral surface of the drum, which is diametrically opposed to the first section. The sensory circuit may also serve for determining the value of balance of the drum. If the balance value is high, no or little imbalance, that means no or little unbalanced distribution of load over the circumference of the drum exists.

By providing at least one balancer at the drum of the washing machine, the load on sections of the drum can be adapted. In particular, the load can be adapted by moving the at least one balancing weight in the mass channel closer to the longitudinal axis or away from the longitudinal axis of the drum. In one embodiment, the balancing is moved in the radial direction. The closer the balancing weight is positioned to the longitudinal axis of the drum, the smaller its influence on the centrifugal force. The further the balancing weight is positioned away from the longitudinal axis of the drum, the higher the influence on the centrifugal force. By changing the centrifugal force in the area of the balancer, an unbalanced distribution of the laundry in the drum can be compensated. Thereby, an imbalance during rotation of the drum and thus vibration during rotation and in particular during spinning can be avoided.

According to one embodiment, the washing machine comprises a positioner for changing the position of the balancing weight within the mass channel from a first distance perpendicular to the longitudinal axis of the drum to a second distance perpendicular to the longitudinal axis of the drum, in response to the determination of the unbalanced load by the sensory circuit. The positioner can also be referred to as actuator or moving unit. The positioner serves for changing the position of the balancing weight. In particular, the position of the centre of mass of the balancing weight is changed by the positioner. Preferably, the positioner changes the position of the balancing weight within the mass channel from a first radial distance perpendicular to the longitudinal axis of the drum to a second radial distance perpendicular to the longitudinal axis of the drum. The positioner preferably acts on the balancing weight in a contactless manner. In particular, the positioner causes the balancing weight to move without physically contacting the balancing weight. The positioner preferably acts on the balancing weight in response to the unbalanced load determined by the sensory circuit. For this reason, the positioner can be activated or deactivated or its influence on the balancing weight can be changed depending on the determined unbalanced load. With this embodiment, the targeted compensation of unbalanced load in the drum can be reliably achieved.

The positioner can be attached to the drum. Alternatively, the positioner is separate to the drum. In this case, the positioner can either rotate around the drum or the positioner is stationary. If the positioner is separate to the drum but rotates around the drum, the positioner can be rotated at the same speed as the drum. If the positioner is stationary, it can for example be fixedly mounted within the cabinet of the washing machine. In the case, where the positioner is attached to the drum or is separate to the drum but is moved at the same speed as the drum, the position of the positioner on the circumference or outside the circumference of the drum is aligned with the position of the balancing weight. In the case, where the positioner is stationary, the positioner will only act on the balancing weight when the balancing weight passes the positioner while the drum is rotated.

According to a preferred embodiment, the balancing weight comprises a ferrimagnetic material and the positioner comprises a magnet for changing the position of the balancing weight within the mass channel. In this embodiment, the positioner acts on the balancing weight by magnetic force. In particular, depending on the magnet or the orientation of the magnet, the balancing weight can be drawn towards the magnet or repelled by the magnet.

In the case where the positioner comprises a magnet, the positioner preferably include means for switching the magnet, in particular for changing the orientation of the poles of the magnet relative to the drum.

According to one embodiment, the positioner comprises means for turning the magnet for changing the position of the balancing weight within the mass channel. In particular, the magnet is turned around an axis, which is perpendicular to the radius of the drum and is a passant line to the circular cross section of the drum. In this embodiment, the magnet can be a permanent magnet. By turning the magnet, the pole of the magnet, which faces the drum and thus the balancer, can be changed. Thereby, in one position, where one pole faces the drum and thus the balancing weight, the balancing weight can be drawn towards the magnet and in the opposite position, where the other pole faces the drum, the balancing weight is repelled by the magnet and thus moved away from the magnet. The magnet can also be a switchable magnet with permanent magnets.

By providing a positioner for turning the magnet, the position of the balancing weight in the mass channel can be changed in a simple manner.

According to one embodiment, the magnet of the positioner is an electromagnet. This embodiment is advantageous as the magnetic field of an electromagnet can be adjusted and the magnet can be switched on and off. Thereby, the direction and the strength of the force which is applied to the balancing weight can be adjusted.

According to one embodiment, the sensory circuit is arranged to take a first balance measurement when the balancing weight is at a first distance from the longitudinal axis of the drum and take a second balance measurement when the balancing weight is at a second distance from the longitudinal axis of the drum. The first and second distances are preferably radial distances. By taking at least these two balance measurements, the distance, preferably the radial distance, of the balancing weight where the balance measurement is high can be determined and the machine can be operated with the balancing weight at this distance from the longitudinal axis of the drum for subsequent rotations of the drum.

According to one embodiment, the positioner is therefore preferably adapted to move the balancing weight to a distance from the longitudinal axis of the drum, where the determined balance measurement is higher.

According to a preferred embodiment, the washing machine comprises a plurality of the balancers. Each of the balancers comprises a mass channel and a balancing weight. This embodiment is advantageous, as the distribution of the load of laundry within the drum can be compensated more precisely. The balancers can be distributed evenly over the circumference or the length of the drum. The balancers can, however, also be distributed in an uneven manner. In particular, two or more balancers can be arranged close to one another. In this embodiment, the neighbouring balancers can also be referred to a group of balancers.

According to one embodiment, at least two balancers or groups of balancers are located at two different distances along the longitudinal axis from the open end of the drum. This embodiment is advantageous as a difference in distribution of the load of laundry over the length of the drum, namely in the direction of the longitudinal axis, can be taken into account and unbalanced distributions at different locations along the length of the drum can be compensated.

According to one embodiment, the balancers are positioned in such a way, that two balancers or groups of balancers are diametrically opposed. This embodiment is advantageous, as the imbalance can be influenced and thereby compensated from two points.

According to one embodiment, the balancers are located, such that the angular distances between the balancers or groups of balancers with respect to the longitudinal axis of the drum are equal.

This means that the balancers or groups of balancers are evenly distributed over the circumference of the drum. With this positioning of the balancers, a compensation of imbalance can reliably be ensured. If several balancers, for example three balancers, are arranged next to each other in a group and several groups are provided, the groups of balancers can be located, such that the angular distances between the centre points of the groups of balancers with respect to the longitudinal axis of the drum are equal.

According to one embodiment, the balancers or groups of balancers are located such that the angular distances between the balancers or groups of balancers with respect to the longitudinal axis of the drum is 90°. In this case, the balancers or groups of balancers are provided at four positions of the circumference of the drum, wherein two pairs of positions are diametrically opposed. In case of groups of balancers, in this embodiment, the groups of balancers can be located, such that the angular distances between the centre points of the groups of balancers with respect to the longitudinal axis of the drum is 90°.

According to one embodiment, the mass channel extends into the drum in a direction between the longitudinal axis and the lateral surface of the drum perpendicularly. This means that the mass channel extends in a radial direction. If several balancers and thereby several mass channels are provided in a group next to each other, the mass channels of the group can also be parallel to each other. In this case at least one middle mass channel of the group of balancers can extend radially.

Additionally or alternatively to its extension inwardly into the drum, the mass channel can also extend outwardly from the circumference of the drum. Also in this case, the mass channel or at least one middle mass channel of a group of balancers extends in a radial direction outwardly.

According to a further aspect, the present invention relates to a method of increasing the balance of a drum rotating along its longitudinal axis within a washing machine, the method comprising

-   -   determining the unbalanced load of the laundry received by the         drum; and     -   moving a balancing weight in a direction between the lateral         surface and the longitudinal axis of the drum.

Features and advantages which are described with respect to the washing machine of the invention—as far as applicable—are also valid for the method according to the invention and vice versa.

Preferably, determining the unbalanced load of the laundry received by the drum is the determination of the position of the unbalanced load of the laundry. In addition or alternatively, determining the unbalanced load of laundry may comprise measuring the value of balance.

By determining the unbalanced load of the laundry, the direction and/or amount of movement, which is necessary for compensating the imbalance, can be determined. As determining the unbalanced load preferably comprises determining the position of the unbalanced load, the selection of a balancer to be used is possible. In particular, a balancer at or close to the position of unbalanced load may be selected for compensation of the imbalance.

According to the invention, the method comprises the step of moving a balancing weight in a direction between the lateral surface and the longitudinal axis of the drum. The moving of the balancing weight can be used for both, the determining of the unbalanced load and for compensating the determined unbalanced load. The movement of the balancing weight is preferably a movement in the radial direction. The movement can be in a direction towards the longitudinal axis or away from the longitudinal axis.

According to a preferred embodiment of the method, determining a position of the unbalanced load of laundry comprises taking a first balance measurement when the balancing weight is at a first distance, taking a second balance measurement when the balancing weight is at a second distance and comparing the first balance measurement and the second balance measurement. The first and second distance are preferably radial distances from the longitudinal axis. By changing the distance of the balancing weight from the longitudinal axis of the drum and comparing the respective balance measurements, it is possible to determine the influence of the balancer, whose balancing weight has changed position, on the imbalance. Thereby, the position of the imbalance can be determined. In addition, by this comparison, the preferred distance of the balancing weight from the longitudinal axis of the drum of that balancer can be determined and used for subsequent rotations of the drum.

If several balancers are provided, the setting of one or more balancers, in particular the distance of their balancing weight from the longitudinal axis of the drum, can be changed simultaneously or subsequently. It is also possible to change the setting of two balancers for determining the unbalanced load while the setting of additional balancers remains unchanged. In this case, preferably the settings of diametrically opposed balancers is changed.

Preferably, the method comprises moving the balancing weight in a direction between the lateral surface and the longitudinal axis of the drum to where the balance measurement is higher. The movement of the balancing weight is preferably a radial movement.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure will be more readily appreciated by reference to the following detailed description when being considered in connection with the accompanying drawings in which:

FIG. 1 is a schematic view of a washing machine with clothes at one point of time;

FIGS. 2 a to 2 d are schematic views of the drum of an embodiment of the washing machine according to the invention at four different positions during drum rotation;

FIG. 3 is a schematic view of the drum of embodiment the washing machine according to FIG. 2 with positioners;

FIG. 4 is a schematic sectional view of one embodiment of a balancer; and

FIG. 5 is a schematic sectional view of another embodiment of a balancer.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

In the following, the invention will be explained in more detail with reference to the accompanying figures. In the Figures, like elements are denoted by identical reference numerals and repeated description thereof may be omitted in order to avoid redundancies.

In FIG. 1

It will be obvious for a person skilled in the art that these embodiments and items only depict examples of a plurality of possibilities. Hence, the embodiments shown here should not be understood to form a limitation of these features and configurations. Any possible combination and configuration of the described features can be chosen according to the scope of the invention.

FIG. 1 shows an embodiment of a washing machine 1. The washing machine 1 comprises a cabinet 4 with a front opening. Inside of the cabinet 4 a drum 2 is received. The drum 2 is rotatable around its longitudinal axis 8. The drum 2 has an open end, which faces the opening of the cabinet 4. In FIG. 1 laundry is schematically shown inside the drum 2. The laundry is shown at two locations. In particular, one portion of the laundry L1 is at the bottom of the inside of the drum 2 and the other portion L2 is at the top of the inside of the drum 2. Such distribution of the laundry can occurs during rotation of the drum 2, in particular during high-speed spinning.

FIGS. 2 a to 2 d show the distribution of the laundry at different rotation states of the drum 2. In particular, FIG. 2 b shows the distribution of the portions of laundry L1 and L2 after rotation of the drum 2 by 90° starting from the state of FIG. 2 a . FIGS. 2 c and 2 d show the state at further rotation by 90°.

In each state shown in FIG. 2 , the portions of load L1 and L2 create pressure to the inside of the drum 2 and created centrifugal force are different at different times during drum rotation.

At a time t, the larger portion of load L1, which may for example have a weight of 4 kg creates a centrifugal force X and the smaller portion of load L2, which can for example have a weight of 3 kg creates a centrifugal force Y. Any difference between the centrifugal forces X and X causes unbalance.

In FIG. 2 groups 50 of balancers 5 are provided at the drum 2. In particular, at the top and bottom of the drum 2 a group 50 of three balancers is provided, respectively. At the sides of drum 2 a group 50 of two balancers 5 is provided respectively. In FIG. 2 only the balancing weights of the balancers 5 are shown.

As can be derived from FIG. 2 , the balancing weights of the group 50 of balancers 5 at the location, where no portion of the laundry is present, are in an initial state. In the depicted embodiment, in this initial state the balancing weights are positioned such that they extend over the circumference of the drum inwardly and outwardly to the same amount.

The balancing weights of the group 50 of balancers 5 at the location of the larger portion of load L1 are moved from such an initial state inwardly into the drum 2. Thereby, the distance between the longitudinal axis 8 of the drum 2 and the balancing weight of each of the balancers 5 of the group 50 is smaller than in an initial state. The balancing weights of the group 50 of balancers 5 at the location of the larger portion of load L2 are moved outwardly from the circumference of the drum 2. Thereby, the distance between the longitudinal axis 8 of the drum 2 and the balancing weight of each of the balancers 5 of the group 50 is larger than in an initial state. Thereby, the centrifugal force which is generated at the position of the smaller portion L2 is increased, whereas the centrifugal force which is generated at the position of the larger portion L1 is decreased and the imbalance is decreased and preferably removed.

In FIG. 3 the drum 2 of an embodiment of the washing machine of the present invention is shown with positioners 7. In this embodiment, four groups 50 of balancers 5 are provided on the circumference of the drum 2. As in FIG. 2 , also in FIG. 3 only the balancing weights of the balancers 5 are shown. Each group 50 of balancers 5 has two balancers 5. The groups 50 of balancers 5 are provided at an angular distance with respect to the longitudinal axis 8 of the drum 2 of 90°. The balancing weights of the balancers 5 are magnetic. Preferably the balancing weights consist of ferrimagnetic material.

In the embodiment shown in FIG. 3 , four positioners 7 are provided. The positioners 7 are magnets M1, M2, M3, M4. The magnets M1, M2, M3, M4 can be permanent magnets or electromagnets. The positioners 7 can be mounted to the cabinet 4 (see FIG. 1 ) of the washing machine 1. The positioners 7 can be stationary with respect to the drum 2. In particular, the positioners do not rotate around the longitudinal axis 8 of the drum 2. In the depicted embodiment, the positioners 7 can, however, be turned about an axis so that different sides of the positioner 7 can be facing the outside of the drum and thus the balancers 5 at different times. This is schematically shown in FIG. 3 by the curved arrows. The movement of the positioners 7, in particular the turning of flipping over of the positioners 7, can be controlled by a control unit (not shown) which can be the control unit of the washing machine 1 or a separate control unit. In particular, the control unit is a microcontroller unit, MCU.

At the beginning of a wash cycle or spinning cycle, the control unit does not know, that the portion of the load L2 at the bottom of the inside of the drum 2 is larger than the portion of the load L4 at the top of the inside of the drum 2. The control unit may therefore assume any point of the drum 2 or the respective weight acting on that point to cause unbalance. The control unit can then activate the positioner 7 at that assumed point or close to that assumed point. In particular, the respective magnet M1, M2, M3, M4 is turned to either attract or repel the balancing weight of the balancer 5. The balance of the drum is measured until the sensory circuit detects the highest balance measurement, i.e. lowest unbalance measurement. Instead of assuming a point, where the load which causes the unbalance is located, the control unit may also sequentially change the position of each balancer or group of balancers 5 to determine the appropriate adjustment of the balancing weights for compensating imbalance.

For example, the method can carried out in such a way, that only the balancing weight of the balancers 5 where the portion of load L1 has accumulated, is moved in and out by means of turning magnet M1 and the other magnets M2, M3, M4 remain in an initial position. The control unit in this embodiment can measure the unbalance of the drum at the position of the balancing weight of the balancer 5 close to magnet M1 being moved out and at a position of the balancing weight of the balancer 5 close to magnet M1 being moved into the drum. The setting of the magnet M1 which provides the highest balance measurement, can then be used for subsequent spinning. The same measurement can be carried out for the other portions of load L2, L3 and L4 and the respective setting of the magnets M2, M3 and M4 can be determined.

Another embodiment of the method according to the invention will now be described with reference to FIG. 3 . At an initial state all magnets M1, M2, M3, M4 are arranged such that the same side is facing the circumference of the drum 2. For example all magnets are turned such that their repelling side is facing the drum 2 and thus the balancers 5. The control unit measures the unbalance of the drum 2 at that state. The rotational speed of the drum 2 may for example be 60 rpm (rotation per minute). This means that the drum 2 rotates one round per 1 second. Since four magnets M1, M2, M3, M4 are provided, the portions of load L1, L2, L3, L4 inside the drum pass a magnet every 0.25 seconds.

At the beginning, the control unit for example assumes that the portion of load L3 shown on the right side of the drum 2 in FIG. 3 cause unbalance. At that stage, the magnets M2 and M4 may remain in a position, where the attracting side faces the drum 2. Magnet M1 is rotated so that its repelling side faces the drum 2 to decrease centrifugal force of unbalanced load and magnet M3 remains in the position, where the attracting side faces the drum 2 to decrease centrifugal force of unbalance. Every 0.25 seconds the unbalance load changes its position and the magnets M1, M2, M3, M4 rotate accordingly. During this process the control unit measures the unbalance.

The control unit repeats the steps mentioned above, but every time the control unit assumes a different portion of load L1, L2, L3, L4 to cause the unbalance, adjusts the orientation of the magnets M1, M2, M3, M4 accordingly and the control unit measures unbalance.

After the above steps, the control unit determines which portion of load L1, L2, L3, L4 causes unbalance. The spinning process is then continued with the magnets M1, M2, M3, M4 being adjusted to compensate the unbalance depending on that determination.

In FIGS. 4 and 5 embodiments of balancers 5 according to the invention are shown. In the embodiment of FIG. 4 , the balancer 5 has a mass channel 3 which is open at its ends. The balancing weight 6 has an oblong shape and may be a rod. The length of the balancing weight 6 is longer than the length of the mass channel 3. In this embodiment the balancing weight 6 has an enlarged diameter at its longitudinal ends to prevent the balancing weight 6 from escaping the mass channel 3. In the embodiment of FIG. 5 , the mass channel 3 is closed at both ends and the balancing weight 6 is received in the mass channel 3. The balancing weight 6 has a shorter length than the mass channel 3, so that the balancing weight 6 can move within the mass channel 3.

The position of the balancer 5 can be such that the mass channel 3 extends through the lateral surface of the drum 2 (see FIG. 4 ) or that the mass channel 3 is attached to the inside of the lateral surface of the drum 2 (see FIG. 5 ).

The principle of the invention is to create balanced opposite side of unbalanced load to absorb unbalance and to reduce centrifugal force of unbalance load.

During the spinning phase of a washing machine, the drum turns with high speed so that clothes can create pressure on the inner surface of the drum due to centrifugal force. This pressure force of clothes cause unbalance. With the present invention, a force can be created at the opposite side of drum to the point where the centrifugal force due to the clothes acts. This force can absorb the force generated by the clothes and can thus reduce unbalance.

During spinning cycle clothes expand inside the drum randomly and aimlessly. Some clothes accumulate at any point of the drum more than at other point and this unbalanced distribution creates pressure on this point and at the opposite side of this point clothes may also come together. If the portions of laundry or amount of clothes that accumulate at opposite sides of any point are the same, these loads absorb each other. However, if not the same amounts of load accumulates on opposite points, there is more pressure on the point which clothes amount to more than at the opposite side.

According to one embodiment of the invention, at least one balancer, which can also be referred to as a moving pin, is provided at the drum of the washing machine. This balancer can be moved from the inside to the outside of the drum and vice versa. This movement can be controlled by a micro controller. If there is less load on one side of the drum than on the opposite side of any point, the pin(s) move outside of the drum at this point which has less load located and the pin(s) move inside of the drum on the opposite side of the point which has less load located.

LIST OF REFERENCE NUMERALS

-   1 washing machine -   2 drum -   3 mass channel -   4 cabinet -   5 balancer -   50 group of balancers -   6 balancing weight -   7 positioner -   8 longitudinal axis -   M1 magnet -   M2 magnet -   M3 magnet -   M4 magnet -   L1 portion of load of laundry -   L2 portion of load of laundry -   L3 portion of load of laundry -   L4 portion of load of laundry 

1. A washing machine (1) comprising; a cabinet (4); a drum (2) for receiving laundry from its open end, wherein the drum (2) is rotatable around its longitudinal axis (8) within the cabinet (4), a balancer (5) comprising a mass channel (3) and a balancing weight (6), wherein the mass channel (3) at least extends in a direction from the lateral surface of the drum (2) to the inside of the drum (2) and receives the balancing weight (6), and the balancing weight (6) is movable within the mass channel (3) along the direction of the extension of the mass channel (3).
 2. The washing machine according to claim 1, wherein the washing machine (1) comprises a sensory circuit for determining the unbalanced load of the laundry received within the drum (2); and a positioner for changing the position of the balancing weight (6) within the mass channel (3) from a first distance perpendicular to the longitudinal axis (8) of the drum (2) to a second distance perpendicular to the longitudinal axis (8) of the drum (2), in response to the determination of the unbalanced load determined by the sensory circuit.
 3. The washing machine according to claim 1, wherein the balancing weight (6) comprises a ferrimagnetic material and the positioner (7) comprises a magnet (M1, M2, M3, M4) for changing the position of the balancing weight (6) within the mass channel (3).
 4. The washing machine according to claim 3, wherein the positioner (7) comprises means for turning the magnet (M1, M2, M3, M4) for changing the position of the balancing weight (6) within the mass channel (3).
 5. The washing machine according to claim 3, wherein the magnet (M1, M2, M3, M4) is an electromagnet.
 6. The washing machine according to claim 2, wherein the sensory circuit is arranged to take a first balance measurement when the balancing weight (6) is at the first distance from the longitudinal axis (8) of the drum (2) and take a second balance measurement when the balancing weight (6) is at the second distance from the longitudinal axis (8) of the drum (2).
 7. The washing machine according to claim 6, wherein the positioner (7) is adapted to move the balancing weight (6) to a distance from the longitudinal axis (8) of the drum (2), where the taken balance measurement is higher.
 8. The washing machine according to claim 1, wherein the washing machine (1) comprises a plurality of the balancers (5).
 9. The washing machine according to claim 8, wherein at least two balancers (5) are located at two different distances along the longitudinal axis (8) from the open end of the drum (2).
 10. The washing machine according to claim 8, wherein the balancers (5) are located, such that the angular distances between the balancers (5) with respect to the longitudinal axis (8) of the drum (2) are equal.
 11. The washing machine according to claim 8, wherein the balancers (5) are located such that the angular distances between the balancers (5) with respect to the longitudinal axis (8) of the drum (2) is 90°.
 12. The washing machine according to claim 1, wherein the mass channel (3) extends into the drum (2) in a direction between the lateral surface and the longitudinal axis (8) of the drum (2) perpendicularly.
 13. A method of increasing the balance of a drum (2) rotating along its longitudinal axis (8) within a washing machine (1), the method comprising determining the unbalanced load of the laundry received by the drum (2); and moving a balancing weight (5) in a direction between the lateral surface and the longitudinal axis (8) of the drum (2).
 14. The method of increasing the balance of a drum according to claim 13, wherein determining a position of the unbalanced load of the laundry received within the drum (2) comprises taking a first balance measurement when the balancing weight (6) is at a first distance from the longitudinal axis (8) of the drum (2), taking a second balance measurement when the balancing weight (6) is at a second distance from the longitudinal axis (8) of the drum (2) and comparing the first balance measurement and the second balance measurement.
 15. The method of increasing the balance of a drum according to claim 14, wherein the method comprises moving the balancing weight (6) in a direction between the lateral surface and the longitudinal axis (8) of the drum (2) to where the balance measurement is higher. 